Maguras and Airfoil noise?

Hey, i installed my maguras today, and they have a shocking noise !

it is very loud and sounds terrible, i bet it could be heard from half a mile away. i’m sure you all know what it sounds like, that weird pitch vibratey noise.

is there any solution to this problem or do i just have to put up with the loud noise?

Thanks for the help, really appreciate it.

sorry about the pic quality, camera phone

edit: oh yeah just incase your wondering, she weighs ~ 10kg, without the waterbottle.

have you tried spraying WD40 around the rim, works well.

i imagine it would greatly affect my stopping power.

the noise of maguras rocks. i know what you mean :slight_smile:

i like it :smiley:

I presume it’s only when you pull the brakes on? The angle of the pad to the rim can affect this, you want the pads angled such there is a slightly larger gap at the front of the pad than the rear, so that the rear-most section contacts the rim first. If the front edge catches first it can vibrate in the manner that you described. I’ve never had this problem on magura shod unis but it’s genreally an issue with bike brakes.

And for goodness sake get some grips on your handles before you beat the c*** out of them! (and it looks sweet)

the pads seem to be hitting the rim dead straight on, so not sure, hmm. but good idea i like the reasoning.

and yes i will get some grips for it soon, had a bad accident a while ago and the right handle is bent down about an inch below the other one and its all scratched up, gotta bend it back and whack a grip on.

I have no experience with 36:er unicycles (but with trials bikes), but perhaps some ideas (questions really at this stage):

  • What pads are you using?
  • There doesn’t seem to be a proper (machined) braking surface?
  • Spoke tension ok?
  • Properly trued wheel?
  • All bolts properly secured?
  • Pads and rim are clean?
  • Pads and rim are worn in?
  • Brake is proberly adjusted (toe in/out issues)?

Maguras can cause a lot of resonance in rims, frames etc… can you tell what is making the noice? (This is hard on a bike since all resonance sounds tend to eminiate from the down tube, because it’s usually quite thin.)

A booster eliminated much of the resonances on my trials bike, but there you grind your rim and use very odd pads. Anyway, check the above questions if noone with more experience in this exact Magura application comes along. :slight_smile:

thats a great response 412, thanks !

the pads im using are red in colour. dont know what that means. they’re second hand.

the airfoil surface seemes ok

the tension and wheel trueness appears ok

bolts are tigtened

not sure abotu the rim and pads being clean, probably not.

pads are worn in to another rim, and my rim isnt worn in.

the toe seems to be ok.

yeah there is a lot of resonance build up in the frame i think, but im not sure

i shall check these things out soon !

THANKS

Ditto 412, I have never owned a 36er, but I had maggies on my mod, and I know people with cokers. The brakes on my mod sqawked loudly, but I suspect that was a product of the ground rim. Your problem probably has something to do with the paint on the rim sidewall. You can wait it out (the pad friction will remove the paint rather quickly), or simply sand the sidewalls down until you see bright silver. Of course, make sure everything is nice and tight if you haven’t already. Also, be sure your pads are parallel to the sidewalls. If you can’t figure it out just adapt and use your brakes as a combination horn/brakes/air raid siren.

I had the same issue on both my Coker and my Muni. kington99 gave the answer. Having the front edge of the pad a little further away from the rim will take care of it.

That’s toe-in, and I thought it was the other way around? Either way, I think magura say that their brakes shouldn’t be aligned like this, so parallel is what you want.

The red pads are trials pads - they’re intented to be either on (wheel locked to hop around on it) or off. Black pads are the standard, or green for wet weather, or grey for ceramic rims (I think). You could try that.

The other thing is to try greasing the mounts and bolts and things - remove the pads first. For disc brakes grease or copper slip on the back of the pads is suggested, but I don’t know if that transfers to non-metallic magura pads. I suspect not.

John

Actually Maguras are supposed to be flat to the rim surface, not toed-in. Toeing isn’t really that effective since the pads float.

Your noise will go away with some riding/use. Essentially the rim/pad have to scour one another for a little while. You can hasten the process by sanding the surface of the pads and the rim, but typically it’s road grit or mud that are required to quiet your system down. If you can do some downhill riding in a light rain or mist, that will pick up grit nicely.

The powdercoating on the more recent Airfoils should make this process take much longer than on a machined rim or anodized rim.

yea but you arent trying to stop the wheel dead, i did it on my muni and there is next to no difference

if theres next to no difference theres no point doing it then eh?

i think i’ll try this toe thing before spraying it.

next to no difference in braking power, at least for a unicycle that is, but it stops the noise

dodgey fix really, probably wont work because my rim is powdercoated and ive got different brake pads to you.

One more “question”:

  • Do the “braze-on”/“magura” mounts on the frame have paint on them?

Sometimes with discbrakes etc, you have to clean/mill the mounting surface to avoid noise. However if everyone else runs maguras with painted mounts, you too should be able to…

You write “other rim”, I take that it’s not a 36 inch rim? Otherwise what happens with that rim…

In trials pads and rim surface make a HUGE difference in sound levels, perhaps your rim is to grippy causeing vibrations due to it’s grabbiness?

Red pads probably mean original magura pads för muddy conditions, they wear faster but brake harder then the normal black ones. There are a myriad of aftermarket special trial pads, but that’s not what you want and likely have. (Red is basically V brake code for mud. :wink:

If you are not worried about appearances (it’s going to get “ruined” anyway after some usage) try gently sanding the rim to remove the anodizing/paint or whatever the black colouring conists of.

As I mentioned before It’s hard to find the source of the resonance due to the fact that it travels through the “whole” uni/bike and the biggest, most thin walled structure tends to act a the primary source of sound (despite the resonande origination from somewhere else).

Do the resonance sound like metal or …?

EDIT: A lot of post appeared after I posted, which answered some of my above questions.

With the new information I would say that the powdercoat is you problem, rubber against paint…

Is the powdercoated rim meant to be used with brakes? (Is there not a machined sidewall version for brake usage?)

i believe the airfoil is designed to be used with a rim brake, but in this batch i think they powdercoated it cause they fucked it up and had to resize it, so that may be the problem.

i think i will leave them how they are for now with the red pads, probably spray some wd40 on there and check the toe, and if that doesnt work maybe get some black pads and consider scraping the sidewall.

I would call that toe-out, but I’m taking that deffintion from setting steering arms on cars, if the wheels point outwards then it’s toe-out. U-turn makes the good point that the pads float anyway, so you might aswell set them parallel.

Magura does recommend parallel pads, but the toe in/out whatever fixed a horrible noise immediatley on both my Muni and 36er without any noticible difference in braking. Of course I’m known to not always follow directions.